What is this?

[bigalatt]

Hey guys...I just got my son a 2003 (ish) suzuki jr50 as his first bike. It runs great and overall is in good shape. However as I was going over everything I noticed a little brass nipple on the cylinder just past this intake track for the carb that I cant figure out what its for. I dont see it on the parts diagram on partzilla or the like. I dont think its part of the lubrication system but im completely stumped. Here's a pic. Any ideas?

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[my67xr]

hi, welcome to Miniriders,

dont forget to drop by and say g'day in our Introduce Yourself thread too while you are here.


that is the Oil Feed pipe to the engine for the 2 stroke oil, there will be a pipe coming from the oil tank (under the seat?)

if it has been disconnected, and you are premixing your fuel/oil, then that barb needs to be blocked off, otherwise it will run very lean, and burn the piston/rings etc.

 

[my67xr]

lol, too quick for me you have already been to the Introduce Yourself thread.

 

[bigalatt]

My first thought was that it might be for the lubrication system but takeba looj at this pic. The oil tank (the white thing) is connected to the motor. If there's another outlet somewhere that should be connected to that nipple I cant find it.

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[my67xr]

ok,
i just found this picture of the JR50 carby, maybe this hose off the middle of the carby runs to that barb ?

 

[bigalatt]

Hmmm...good find. I'll take a look at it tmo afternoon and let you know. Thanks!

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[my67xr]

nah i found out that carby hose doesn't go to the vacuum post, it's just a vent hose.



but, i have worked it out

here it is,
shown on an early '83 model JR50,
possibly your engine has been swapped or just the barrel ?
http://www.cmsnl.com/suzuki-jr50-r-1983-usa_model16131/partslist/90309.html#results


looks like the early models Suzuki 50's had an oil pump that sucked oil in, then sent it back out and into that barb intake, ( shown in the picture above)

http://www.dreyermotorsports.com/oe..._Inc/FA50_(1991)/OIL_PUMP/06050010/5606050008

 

[bigalatt]

Ok..let me ask if this makes sense. The barrel (or engine) goes to an early-mid 80s bike which is why that nipple is there. I found on a LT 50 forum a description of how to hook up the fuel lines and apparantly that cylinder nipple would have been connected over to the pet**** to provide vacuum. I looked at the pet**** on mine and it matches that of an early 2000 model which only has one outlet which diifers from the 80s ones that had 2. As such I'm thinking I can just put a cap on it to make sure it doesn't suck air and lean the mixture. Does this sound plausible? The only reason I hesitate to think its for oil is because everything I can find about this bike says that once the oil gets to the pump, everything is internal.

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[my67xr]

yeah i first thought about the vacuum operated fuel tap.
they also use them on the Yamaha Chappy 80cc 2T Scooters i'm doing up atm.

so i'd be confident in saying, just block off the barb, use a cap for a carby vacuum blockoff or whatever you can find.
most Auto Parts/Accessories shops would keep them in stock.
this is a Holley Assorted blockoff cap kit-

 

[bigalatt]

Will do. Thanks for your input on this and the links.

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